Modern architectures for distributed object environments (or distributed 'middleware') are revealing an increasing trend towards standardization. The recent emergence of a standard for open distributed process...
High latency and loss rates in the Internet make it difficult to stream audio and video without introducing a large playback delay. To address these problems, we propose a prefix caching technique whereby a proxy stor...
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High latency and loss rates in the Internet make it difficult to stream audio and video without introducing a large playback delay. To address these problems, we propose a prefix caching technique whereby a proxy stores the initial frames of popular clips. Upon receiving a request for the stream, the proxy initiates transmission to the client and simultaneously requests the remaining frames from the server. In addition to hiding the delay, throughput, and loss effects of a weaker service model between the server and the proxy, this novel yet simple prefix caching technique aids the proxy in performing workahead smoothing into the client playback buffer. By transmitting large frames in advance of each burst, workahead smoothing substantially reduces the peak and variability of the network resource requirements along the path from the proxy to the client. We describe how to construct a smooth transmission schedule, based on the size of the prefix, smoothing, and playback buffers, without increasing client playback delay. Experiments with MPEG traces show how a few megabytes of buffer space at the proxy can substantially reduce the bandwidth requirements of variable-bit-rate video. Drawing on these results, we present guidelines for allocating buffer space for each stream, and how to effectively share buffer and bandwidth resources among multiple clients and streams.
In modern circuit design, the Shannon decomposition of switching functions is widely used. On the other hand, in information theory of telecommunication, the Shannon entropy used as a measure to represent the informat...
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In modern circuit design, the Shannon decomposition of switching functions is widely used. On the other hand, in information theory of telecommunication, the Shannon entropy used as a measure to represent the information in numerical values, is a key notion. In this paper, we relate these two concepts, belonging to different areas, into an approach to the minimisation of exclusive-or sum-of-products (AND/EXOR) expressions for switching functions. The Shannon decomposition, and the closely related Davio decomposition for AND/EXOR expressions are interpreted in terms of basic concepts in the information theory. Thanks to that, we have proposed an entropy based strategy for minimization of AND/EXOR expressions. We have provided a comparison and an experimental verification of this strategy with some known heuristic minimization strategies using benchmarks. In some cases, our program Info-EXOR produces extremely better results. Moreover, the information theory interpretation of classical decomposition of switching functions offers a new point of view to the existing design styles.
A novel concurrent programming paradigm called hypersequential programming (HSP) is being developed. HSP aims to eliminate all undesirable behaviours from a given application. A fundamental part of that system require...
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A novel concurrent programming paradigm called hypersequential programming (HSP) is being developed. HSP aims to eliminate all undesirable behaviours from a given application. A fundamental part of that system requires the use of test cases for the serialization of a program. Only those test cases found to be correct are used in the final concurrent program. Therefore, HSP relies on all the functionality being included into a program. This is opposite to traditional software engineering practice, which is to ensure that all unwanted behaviours have been removed. We briefly examine the HSP method with reference to test cases and scenarios. We examine a couple of brief examples and discuss the limitations of test cases, with particular respect to HSP. We conclude that finding a method of ensuring the correct set of test cases is used in development is essential to the success of HSP.
Provisioning network resources for multimedia streaming is complicated by the bursty, high-bandwidth traffic introduced by compressed video, as well as the variability of the throughput, delay, and loss properties of ...
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Provisioning network resources for multimedia streaming is complicated by the bursty, high-bandwidth traffic introduced by compressed video, as well as the variability of the throughput, delay, and loss properties of the Internet, and the lack of end-to-end control by any one service provider. To address these problems, we propose that proxies should perform online smoothing by transmitting frames into the client playback buffer in advance of each burst, to reduce network resource requirements without degradation in video quality. This paper describes the practical systems issues we have encountered in building a smoothing proxy service using off-the-shelf components, in the context of an MPEG-2/RTP streaming testbed.
This paper describes a standard interoperability model based on a knowledge representation language such as Conceptual Graphs (CGs). In particular, it describes how an Electronic Data Interchange (EDI) mapping facilit...
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The diversity of research and development work on agent technology has led to a strong distinction between mobile and intelligent agents. This paper presents an architecture aiming at providing a step towards the inte...
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ISBN:
(纸本)354064959X
The diversity of research and development work on agent technology has led to a strong distinction between mobile and intelligent agents. This paper presents an architecture aiming at providing a step towards the integration of these two aspects, concretely by providing an approach of dynamically embedding negotiation capabilities into mobile agents. In particular, the requirements for enabling automated negotiations including negotiation protocols and strategies, a plug-in component architecture for realizing such requirements on mobile agents, and the design of negotiation support building blocks as components of this architecture are presented.
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